I would have gone off their screens at that point. I was changing out of my gown and using it to strap the ankle in order to move with more alacrity.

The Bethlem sits in large and pretty grounds. It was moved in the 1930s to a former estate. Each department is housed in a separate building. Between them lies an expanse of lawn, criss-crossed with roads and dotted with mature trees. I crouched in the tentlike shelter of a huge fir. It was heady with the stink of fox. I changed swiftly, jarring my sprained ankle as I pulled on the trousers. The wave of pain was remote, like a flash of lightning on the horizon. Someone called out as I hobbled off site; I didn’t know if they’d seen me or not.

I was under no illusions about the extent and minute accuracy of twenty-first-century surveillance. Footage taken from the camera onboard the 119 that I took from the end of Monks Orchard Road would have been corroborated by the usage record of the travelcard, and there were four or five other passengers on the night bus if they needed witnesses. But I was gambling that I was ten or fifteen minutes ahead of them, and that there was still one place where I could count on hiding.

Mitcham Common in the darkness was as remote and quiet as the Peak District. It was almost daylight by the time I got home and I was half afraid that I would run into the Mauritian milkman. There was a For Sale sign outside the house. The spare keys were in their plastic bag under the acanthus.

I lay down to sleep in the cupboard under the eaves, but before going to sleep, I couldn’t stop myself wandering round the house. The downstairs and the children’s rooms had been emptied. It looked bigger without the furniture. There were ghostly negatives on the walls where Lucius and Sarah’s posters had once hung. My study was largely untouched. There was still a hundred pounds in my copy of Borras and Christian’s Russian Syntax. I picked up my father’s Parker 45 and was shocked how small it seemed in my adapted hand. ‘My name is Nicky Slopen,’ I wrote on the back of an envelope in faltering ink.

*

Later that day, I was woken by muffled sounds and the ingratiating voice of an estate agent: ‘… plenty of storage space,’ he said, as he opened the door close to my feet. There was a flash of sunlight and he shut it again. I held my breath. ‘The couple who lived here have sadly split up.’ He made no mention of my murder. He didn’t want to trouble them with the gloomy association. The woman asked if it was in the catchment area of Lucius’s old school. And down they went. I waited for the clump of the front door before venturing out of the cupboard.

I wondered if the police would bring themselves to look for me here. It was in a sense the obvious place, but in another it presented a problem for Dr White. He had to disparage my claims that I was who I said I was. It would be politically difficult for him to admit that I might be in here.

As it turned out, they didn’t check the house for five days, by which time I had created a false back for the cupboard with sheets of plywood. I slept during the day and only emerged after nine to buy vacuum-packed food from the Tamil grocers, whom I trusted because their support for the Sri Lankan separatist movement made them constitutionally hostile to the police. I also brought home bags of ice for my ankle. I went in and out along the alleyway between the houses to avoid the neighbours.

The police made a perfunctory search of the premises around noon on the day they came. Nothing they might have seen would have aroused suspicion. I could see one of them through the keyhole. I could even smell his aftershave. That evening, I slipped out of the house for good. Moving there had been one of those haphazard decisions that we took in haste, but which coloured our whole subsequent lives. Lucius would have been born in the front room, but for a last-minute change of heart that saw Leonora heading via ambulance to St George’s. In that house, Leonora and I raised our children and made the billion mundane bargains out of which family life is constructed, arguing about curtains and bedtimes and whose turn it was to put out the recycling. Two years before, in the spare bedroom, we had made love for the last time before going out to dinner; hasty and almost perfunctory, the act still seemed somehow to hold the possibility of future closeness. Leonora straightened her skirt and smoothed the front of her blouse with both hands.

‘We could always have another child,’ I said.

She gave a wry laugh. We both knew that our resources and our relationship were too tenuous to support it.

Even now, the house was charged with an indefinable, heartbreaking scent that constantly brought to mind my children. And while I was in it, I could still pretend I had some kind of link to my old life.

2

I called Misha Bykov from a payphone the day I left the house.

He met me in Richmond Park, just inside the Sheen Gate, where two under-eleven teams of boys were playing rugby in hooped shirts.

By the time he arrived, I had been waiting for him on a bench for almost an hour. It was a bright but raw day. I watched him make his way on foot through the gate. He had on a huge overcoat but no hat and his cheeks were inflamed with the cold.

He didn’t acknowledge me, choosing to stand some distance away, smoking a cigarette, as though we had nothing to do with one another. I began by asking if he’d heard anything of Vera.

‘She’s in a psychiatric hospital in Chita.’

‘Chita? Where’s that?’

‘Siberia.’ He shook his head. ‘Mnogo vody uteklo,’ he said wearily. It’s one of those deceptively simple but dense expressions that’s characteristic of Russian. It literally means ‘a lot of water has flowed’ but carries the sense of belatedness and irreversible change. His face looked more rumpled and underslept than usual. I took it to mean that he’d concluded that our abortive resistance must come to an end.

‘I have a few things for you,’ he said.

It was money, which I accepted gratefully, and an A4 envelope of papers, which I opened in front of him.

Another grainy photocopied passport, this time of a man called Viktor Koryakin. He had thin, fair hair and was fuller in the face, but I recognised something in the furious intensity of his pale eyes, although for a moment I couldn’t remember where I’d seen them. His place and date of birth were given as Krasnodar, September 19th 1978. There were discharge papers from the army, and some police photographs of the same face, this time with a black eye and a bloodstained shirtfront; close-ups of the familiar tattoos.

‘It’s you,’ he said. ‘A roughneck from the Kuban. A real Cossack.’

I felt strangely empty. ‘Does he have children?’

‘I didn’t know him,’ said Misha.

‘What do I do?’

‘You have to live,’ he said. ‘We all do.’

I could hear shrill voices as one of the boys broke away for a try and the sound of the whistle as he touched the ball down to score.

‘There’s more,’ he said.

The envelope seemed empty, but when I turned it out, what looked like a small clear plastic dogtag dropped into the palm of my hand. It was a polygon about an inch and a half in diameter and roughly a quarter of an inch thick. There was a hole bored through the middle. On closer inspection, it was too heavy to be plastic, and there was a strange iridescence around its edges.

‘Quartz,’ he said.

‘Jewellery?’

‘Your klyuchka.’

I knew the word – it’s the diminutive of klyuch, which means ‘key’ in Russian, in a range of senses including a key to a door, a musical key and the key to a cipher. It can also mean a clue, and a spring or source of water.

‘To what?’

‘To you,’ he said. ‘It’s your code. The one Vera wrote.’